The inventive concept relates generally to power management approaches that may be used in mobile devices. More particularly, the inventive concept relates to power management circuits, mobile devices including power management circuits, and methods of adjusting the frequency of an operating clock in view of power supply voltage(s) provided by a battery in the mobile device. In certain embodiments of the inventive concept, the power management circuit will be configured in a power management integrated circuit (PMIC) separate from a computational logic chip or Systems-on-Chip (SoC), such as those including a central processing unit (CPU) controlling the overall operation of the mobile device.
The operational reliability and effective operating duration of battery-powered mobile devices are increasingly important considerations. That is, as users move more and more of their digital computational requirements and entertainment applications to mobile platforms, such as smart phones, smart watches, tablets, etc., the need to usefully extend battery life continues to be an important design and/or operating consideration. In this regard, the battery-powered operation of many mobile devices becomes particularly precarious as charge is drained from the battery below a particular level (i.e., circumstances that generally result in a “low battery” condition). For example, while many functions will continue to be normally executable in a mobile device powered by a low battery, other (more power-hungry) functions may stress the low battery to a point where the mobile device cannot continue to operate. In this regard, a mobile device powered by a low battery becomes increasingly susceptible to operative interruptions (e.g., undesired shut-downs) caused by a sudden momentary power loss (SMPL).
A SMPL may alternately be referred to as a sudden voltage drop (SVD) and may be the result of a certain “power events” caused when a low battery is suddenly (or momentarily) required to provide a relatively high level of current due to some loading effect (e.g., initiation of some high current consuming functionality by a mobile device user). When confronted by this sudden demand for current, a low battery may not be able to maintain at a minimum level one or more signals (e.g., control signals, clock signals, operating voltages, etc.), such as those critically provided to a processor, computational logic, central processing unit, etc. This loss of minimum signal level, even during a relatively brief or transient moment, may cause the mobile device to power-down and/or operate abnormally. As a result, in the absence of such transient and relatively high-current consuming power events, the mobile device might operate for a considerably longer period of time despite the low battery condition.